1. Field
The present invention relates to an organic light emitting display device and a manufacturing method thereof.
2. Description of the Related Art
An organic light emitting display device is a self-luminous display device that displays an image with an organic light emitting element that emits light. Unlike a liquid crystal display (LCD), an organic light emitting display device does not need a light source, so thickness and weight thereof may be reduced.
Also, an organic light emitting display device has high quality characteristics such as low power consumption, high luminance, and high response speed, and the like, so it has come to prominence as a next-generation display device for electronic devices.
In general, an organic light emitting element includes an organic emitting layer (EML) interposed between first and second electrodes, so when a voltage is applied to the respective electrodes, holes supplied from the first electrode and electrons supplied from the second electrode are injected into the organic emitting layer and recombined therein to form excitons as hole-electron pairs, and light is emitted by energy generated as the excitons are returned to a ground state.
The first and second electrodes are connected to wirings corresponding thereto to receive a driving voltage from an external driving unit and apply an electric field to the organic emitting layer.
Meanwhile, the first and second electrodes are electrically connected to the external driving unit (including the wirings) through a contact part positioned in a non-emitting region of a substrate. The contact part may be configured as driving voltage wirings electrically connected to the first or the second electrode through a contact hole, or the like.
The driving voltage wirings positioned in the contact part may be composed of layers including a transparent conductive layer, a gate electrode layer, a data electrode layer, and the like, formed on the substrate, and may be patterned through a collective (or integrated) etching process.
In performing the collective etching process, a lateral surface of a gate electrode layer is etched to have an under-cut structure, and an air gap is generated in the under-cut portion.
The air gap generated due to the under-cut structure may cause cracks or discontinuation of an insulating layer formed on an upper portion of the gate electrode layer, and as a result, an insulating function may be degraded to generate a short-circuit between the gate electrode layer and the data electrode layer.
In addition, after the patterning process formed on the contact part, a cleaning process is performed, and in this case, moisture, or the like, may remain in the under-cut structure to affect a follow-up process, making the contact part defective.